It can be looked at as both an artistic and scientific necessity in the garden, and this removing of spent blooms has some reminiscences of a 1960s band, as we refer to this practice as “deadheading.” The task of deadheading and its many variations and purposes is also called pinching, pinching back, cutting back or disbudding. And this is prime time for all of them, but especially on annuals and a few perennials.In its very basic form deadheading is no more than removing flowers from a plant once they have bloomed and the flowers have faded. In most cases the purpose is to redirect the plant’s energy away from the production of seeds and into growing new and more flowers. In the case of geraniums (the annual types), though, deadheading will reduce the incidence of the Botrytis fungus that changes the spent blooms into fuzzy then gooey masses, and will allow your plants to bloom more vigorously as well as remain healthier.
As a very general rule, as the flowers begin to lose their color or drop some petals the deadheading should begin. Some gardeners do this automatically as a matter of habit just like pulling weeds, but beginners may need to inspect plants on a weekly basis, and gardeners with little spare time will need to know what does need deadheading, what may be optional and what doesn’t need to be touched at all. In time you’ll also learn which flowers and shrubs need to be tended to in this way, but for now let’s look at some general guidelines and then get more specific.
Some of the earliest deadheading work is done on spring-flowering bulbs like daffodils and tulips, but few of us take the time. We pay more attention to the daffodils because they tend to be much more “perennial” than the latter, but tulips that are deadheaded may flower for a couple more years than if permitted to go to seed. Naturalizing daffodils generally are not deadheaded for two reasons. First, in mass plantings of thousands of bulbs it just isn’t realistic to deadhead each flower cluster, and second, most of the naturalizing types have been selected for their ability to produce new bulbs and not spend their energies on seed production. The fancier daffodils will benefit from deadheading and it’s as simple a popping off the seed head that forms as the flowers fade. This can be done one by one or with a shears for large plantings, but be careful not to cut down the foliage, only the seed heads.
Another good example that flowers slightly later in the spring are the creeping phlox, Phlox subulata. This plant can get downright ugly after flowering, as some varieties get long and stringy, especially when grown in any amount of shade. On these plants, once flowering is over a shears or pruner can be used to reduce the mass. The effect of this pruning is not only to remove the spent flowers, but in this case you are causing the plant to send out new growing shoots at each cut … much in the same way that we prune privet to stay compact and full. As a result, the plant will remain compact, full of dense growth and heavily budded for next spring’s show. The perennial alyssum, Iberis (candytuft) and Aubrieta can be handled in the same way—but early in the season, not now.
Moving a bit further into spring, there is the magnificent period when the lilacs are in bloom. If left untended, these shrubs will flower and each flower will try to set seed. Again, our purpose here is to redirect the plant’s energy away from its immediate inclination to reproduce. The common wisdom has always been that shortly after flowering you should have attempted to remove the flower clusters by pinching or pruning them out just below the spent flower. As a result, next year’s flower production will be just as great or better. It was thought that if these plants are not deadheaded each year the flower clusters get smaller and smaller and in some years the shrub may not flower at all.
But one spring I paid particular attention to a large number of lilacs that have been growing in the same place for decades and never appear to be deadheaded or pruned. Almost without exception they looked magnificent during flowering season. Go figure. We are also at the point in the gardening calendar where you should have removed the spent flowers from rhododendrons. It’s amazing how many gardeners ignore this routine and yet it’s imperative to the top performance of many but not all of these plants. It’s beneficial to remove only the faded flowers of the large-leaved or elepidote rhododendrons. This type typically has not only larger leaves but larger flowers than the smaller-leaved lepidote rhododendrons and azaleas, which don’t need deadheading. The elepidotes are most easily distinguished by their large leaves, but they can be positively identified by noticing that the undersides of their leaves are non-scaly as opposed to the elipedotes, which have scales.
In most cases where the old blooms are not removed (on the elepidotes) it takes that branch two years to rebloom. If deadheaded, the branches will bloom every year and you may find your rhodies with twice as many flowers as in previous years. The process is simple. Just pinch or snap the old flower off from just below the flower, but make sure not to remove the newly formed bud or vegetative growth. To do the job properly you really need to look at each old flower head before deadheading, and you will end up with sticky hands. But, if you have never done this to your rhodies before, just watch for the fantastic results next year.
Next it’s back to the flower garden, where Shasta daisies (now called Leucanthemum) have been blooming. Some of the newer hybrid varieties of this plant won’t need deadheading because they don’t set seed, and in this case the only purpose of removing spent blooms is for aesthetics. But the more common varieties of Shastas, as in the older common species, will bloom on for weeks only if they are deadheaded. Look at the stems of this plant, and below the fading bloom move down the stem until you see the formation of a new bud. With a cross-cut (not an anvil-type) pruner or pruning scissors, cut the stem at the leaf axil just above the forming bud. This will work for several weeks, but as the weather gets warmer and the days shorter it’s the tendency of this plant to simply stop forming new buds. Unless you intend on saving the seeds or allow for self-sowing, once the petals of Oriental poppies begin to fall in June it’s time to deadhead. Leaving the seed pods on reduces the formation of foliage below, and it’s the foliage that feeds the roots that produce next year’s flowers. There is a dilemma here, though, because some gardeners like the structural effect that the seed heads give to the garden, and they choose to leave the seed heads on. In this case you may be more likely to find the poppies not overwintering as well, or needing replacement every few years. Remember also that the seeds produced by these poppies that will fall to the ground and germinate may not reproduce true to name and variety, as in color.
Next week, more disbudding and deadheading, but for now go out and take a look at your petunias and marigolds and see what needs to be done. Keep growing.